org.jboss.as.clustering.lock

Class SharedLocalYieldingClusterLockManager

java.lang.Object

org.jboss.as.clustering.lock.SharedLocalYieldingClusterLockManager

public class SharedLocalYieldingClusterLockManager
extends Object

Distributed lock manager intended for use cases where multiple local threads can share the lock, but only one node in the cluster can have threads using the lock. Nodes holding the lock yield it to remote requestors if no local threads are using it; otherwise remote requestors block.

The expected use case for this class is controlling access to resources that are typically only accessed on a single node (e.g. web sessions or stateful session beans), with the distributed lock used primarily to guarantee that.

Author:

Brian Stansberry

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SharedLocalYieldingClusterLockManager.LockResult Result of a lock call

Constructor Summary

Constructors

Constructor and Description
SharedLocalYieldingClusterLockManager(String serviceHAName, GroupRpcDispatcher rpcDispatcher, GroupMembershipNotifier membershipNotifier)

Method Summary

Methods

Modifier and Type	Method and Description
SharedLocalYieldingClusterLockManager.LockResult	lock(Serializable lockName, long timeout) Acquire the given lock.
SharedLocalYieldingClusterLockManager.LockResult	lock(Serializable lockName, long timeout, boolean newLock) Acquire the given lock.
void	start() Brings this object to a state where it is ready for normal operation.
void	stop() Removes this object from a state where it is ready for normal oepration and performs cleanup work.
void	unlock(Serializable lockName, boolean remove) Releases a previously acquired lock.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SharedLocalYieldingClusterLockManager

public SharedLocalYieldingClusterLockManager(String serviceHAName,
                                     GroupRpcDispatcher rpcDispatcher,
                                     GroupMembershipNotifier membershipNotifier)

Method Detail

lock

public SharedLocalYieldingClusterLockManager.LockResult lock(Serializable lockName,
                                                    long timeout)
                                                      throws TimeoutException,
                                                             InterruptedException

Acquire the given lock.

Parameters:

lockName - the identifier of the lock that should be acquired

timeout - max time in ms to wait before throwing a TimeoutException if the lock cannot be acquired

Returns:

enum indicating how the lock was acquired

Throws:

TimeoutException - if the lock cannot be acquired before the timeout

InterruptedException - if the thread is interrupted while trying to acquire the lock

lock

public SharedLocalYieldingClusterLockManager.LockResult lock(Serializable lockName,
                                                    long timeout,
                                                    boolean newLock)
                                                      throws TimeoutException,
                                                             InterruptedException

Acquire the given lock.

Parameters:

lockName - the identifier of the lock that should be acquired

timeout - max time in ms to wait before throwing a TimeoutException if the lock cannot be acquired

newLock - true if this object should assume this is the first use cluster-wide of the lock identified by lockName, and just acquire the lock locally without any cluster-wide call. See discussion of SharedLocalYieldingClusterLockManager.LockResult.NEW_LOCK.

Returns:

enum indicating how the lock was acquired

Throws:

TimeoutException - if the lock cannot be acquired before the timeout

InterruptedException - if the thread is interrupted while trying to acquire the lock

unlock

public void unlock(Serializable lockName,
          boolean remove)

Releases a previously acquired lock.

Parameters:

lockName - unique name identifying the lock to release

remove - true if this lock can be removed from tracking once all local locks are unlocked.

start

public void start()
           throws Exception

Brings this object to a state where it is ready for normal operation.

Throws:

Exception

stop

public void stop()
          throws Exception

Removes this object from a state where it is ready for normal oepration and performs cleanup work.

Throws:

Exception